Multi-dimensional (e.g., two dimensional and three dimensional) filamentary preforms have been infiltrated/impregnated with an organic or inorganic matrix material to form filament reinforced composite articles. The reinforcing filaments of the woven or braided preform may comprise a variety of materials including, but not limited to, glass, fused silica, ceramics, carbon, graphite, refractory metals as well as others.
In order to obtain accurately sized and shaped composite articles from woven or braided preforms, it is necessary to maintain a desired preform shape during subsequent handling and infiltration/impregnation of the preform with a matrix material. In some situations the preform may be subjected to some slight machining prior to matrix infiltration/impregnation. The as-woven or braided shape must be maintained during this operation as well.
The problem of shape integrity of the woven or braided filamentary preform is exacerbated when the preform must include thin sections (e.g., feather edges) that are easily distorted during subsequent handling, machining and matrix infiltration/impregnation.
There is thus a need to minimize the shape instability of the filamentary preform and to provide a near final shape preform that can accommodate subsequent handling, matrix infiltration and even light machining prior to matrix infiltration without loss of the near final shape.
It is an object of the present invention to satisfy this need.